Satellite Tracking of Sea Turtles

A project undertaken at the Centre for Indigenous
Natural and Cultural Resource Management, and supervised by
R Kennett

Green turtles are renowned for their long-distance
oceanic migrations between nesting beaches and feeding
grounds, spanning hundreds and even thousands of kilometres.
These migrations often traverse national and international
boundaries, requiring regional cooperation in the
conservation and management of this endangered species.
Understanding migration behaviour and routes, and
identifying the coastal communities and other stakeholders
who share responsibility for green turtles, is a key step in
developing regional cooperation.

Green turtles are an important natural resource to the
Yolngu, the indigenous people of north-eastern Arnhem Land,
who have long held spiritual and cultural responsibilities
for the large numbers of green turtles that nest on their
beaches. Yolngu have been engaged in a sea turtle (miyapunu)
conservation and research project since 1994, combining
traditional ecological knowledge with contemporary research
methods to develop a strategy for the sustainable use of
green turtles. Aware of the need for regional cooperation in
turtle conservation, the Yolngu have used satellite
telemetry to track the migrations of green turtles and so
identify communities with whom they share responsibility for
this migratory resource. To achieve this, radio transmitters
were attached to 20 female green turtles in 1998 and 1999 as
they departed from Djulpan, a major nesting rookery south of
Nhulunbuy on the Gove Peninsula. Location ‘fixes’ received
via satellite allowed the precise migration routes and
locations of their home feeding grounds to be mapped. The
Hermon Slade Foundation provided the funds for five
transmitters and satellite charges, as well as for the
travel costs of researchers.

Contrary to the expectation that these turtles would
disperse widely to feeding grounds as far afield as east
coastal Queensland, Western Australia or even Indonesia and
Papua New Guinea, all turtles remained within the Gulf of
Carpentaria with many sharing overlapping feeding grounds.
Turtles swam about 50 km per day, travelling to feeding
grounds as close as 140 km away in Blue Mud Bay to nearly
720 km away near Bentinck Island in the south-eastern corner
of the Gulf. Most of the turtles returned to feeding grounds
in Limmen Bight or near the Edward Pellew Islands, in the
south-western corner of the Gulf.

These results, coupled with the high fidelity of green
turtles to their chosen nesting beach and feeding ground,
suggest an optimistic management scenario where the Gulf of
Carpentaria green turtle stock may not be threatened by
unsustainable harvests of turtles outside Australian waters.
Hence, the long-term survival of this stock may be largely
determined by the management actions of Australian
Indigenous peoples and conservation authorities. Building on
these results and their experience in turtle research, the
Yolngu are working with other peoples to establish a network
of indigenous communities and promote a cooperative
management strategy for marine turtles in the region.